Pore diameter of mesoporous materials has been tailored by adding fluorocarbons as organic auxiliaries. Characterization results show that perfluoroheptane and perfluorodecalin (PFD) can be effectively used as expander. The pore size is increased from 4.0 to 6.8 nm. However a transition from a well ordered hexagonal arrangement to a wormhole like structure is detected when the oil loading is higher than 2.5 wt.%. Neither the structure nor the pore sizes are influenced by the addition of perfluorooctane.
To better understand the influence of these perfluorocarbons and to shed some light on the mechanism of pore size enlargement, we have studied the effect of this fluorocarbon addition on the surfactant phase behavior and the ternary R F 8 ðEOÞ 9 =oil=water systems have been investigated. Micellar phase (L 1 ), direct hexagonal (H 1 ), cubic (I 1 ) and lamellar liquid crystals were identified. Phase behavior and SAXS measurements proved that only a weak fraction of oil can be incorporated into the hydrophobic core of micelles (L 1 ). However, results also show that the swelling effect of H 1 takes place with PFD, whereas the penetration effect occurs with perfluorooctane.